Higher the degree of decentralisation, wider is the span of management. If a manager clearly delegates his authority, defines it fully, he requires less time to devote to manage his subordinates because most of the actions would be taken by them on their own.

But, if the subordinate do not have adequate authority, or there is ambiguity in the authority, these require frequent consultation and clarification from the superior and they take a disproportionate amount of superior's time. Consequently a manager has to keep his span narrow.